rdblue commented on a change in pull request #24559: URL: https://github.com/apache/spark/pull/24559#discussion_r587672991
########## File path: sql/catalyst/src/main/java/org/apache/spark/sql/connector/catalog/functions/AggregateFunction.java ########## @@ -0,0 +1,73 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.spark.sql.connector.catalog.functions; + +import org.apache.spark.sql.catalyst.InternalRow; +import org.apache.spark.sql.types.DataType; + +/** + * Interface for a function that produces a result value by aggregating over multiple input rows. + * <p> + * The JVM type of result values produced by this function must be the type used by Spark's + * InternalRow API for the {@link DataType SQL data type} returned by {@link #resultType()}. + * <p> + * Most implementations should also implement {@link PartialAggregateFunction} so that Spark can Review comment: @dongjoon-hyun, @sunchao, @viirya, @dbtsai, @wmoustafa, what do you think? Sounds like we have 2 options: 1. Combine the partial interface with the aggregate interface so everything is required to implement the partial methods 2. Add a rule that fails all aggregates that don't support partial aggregation for now. The first option is the easiest, but it means that this API is less expressive. As @cloud-fan noted, partial aggregation doesn't make sense for all aggregate functions. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
